The peroxisome proliferator-activated receptors (PPARs), new members of nuclear hormone receptors were discovered in 1990. Recent developments regarding these receptors were reviewed. The specificity of ligands，the differential tissue distribution as well as target genes are described for each of the three isotypes α、β、γ. Their implication in the control of inflammtory response, lipid metabolism, cell proliferation and differentiation, and the possible role played in chronic diseases such as cancer and atherosclerosis are discussed.